This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-374997, filed Dec. 28, 1999, the entire contents of which are incorporated herein by reference.
The present invention relates to a gel electrolyte precursor, a chemical battery comprising a gel electrolyte obtained from the gel electrolyte precursor, and a method of manufacturing the chemical battery.
A nonaqueous electrolyte secondary battery, which is an example of the chemical battery, comprises an electrode group including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and a nonaqueous electrolyte held by the electrode group. Used as the positive electrode active material is, for example, a lithium-containing complex oxide. Also, the negative electrode is formed of, for example, lithium, a lithium alloy, or a carbonaceous material absorbing-desorbing lithium. On the other hand, a liquid nonaqueous electrolyte prepared by dissolving a lithium salt as an electrolyte in a nonaqueous solvent such as propylene carbonate or xcex3-butyrolactone is used as the nonaqueous electrolyte.
In recent years, it is required to increase the capacity of the battery, to make the battery thinner and to increase the active area of the battery in accordance with miniaturization, reduction in thickness and improvement in the performance of electronic appliances. It is proposed to use a film material such as a laminate film in place of a metal can as a vessel for housing the electrode group in an attempt to decrease the thickness of the nonaqueous electrolyte secondary battery and to make the secondary battery light in weight. In the case of using a film material, however, the liquid nonaqueous electrolyte tends to leak to the outside. Also, the distribution of the nonaqueous electrolyte within the electrode group tends to be nonuniform. As a result, a problem is generated that the cycle characteristics are lowered. In order to avoid the particular problem, it is studied to impart viscosity to the liquid nonaqueous electrolyte so as to lower the fluidity of the liquid nonaqueous electrolyte.
For example, Japanese Patent Publication (Kokoku) No. 61-23944 discloses a solid composition having an ionic conductivity, comprising an electrolyte consisting of ions of metals belonging to Group I and/or Group II of the Periodic Table, an organic high molecular weight compound having a relative dielectric constant smaller than 4, and an organic solvent having an excellent solubility in respect of the electrolyte and the organic high molecular weight compound noted above and also having a relative dielectric constant smaller than 10. It is disclosed that the solid composition having an ionic conductivity contains the electrolyte in an amount sufficient for imparting an ionic conductivity of at least about 10xe2x88x9210 Sxc2x7cmxe2x88x921 to the composition and in an amount not larger than 90 mol % of the solid composition. It is also disclosed that it is desirable to use resins other than thermosetting resins as the organic high molecular weight compound. Particularly, it is disclosed that a satisfactory result can be obtained in the case of using as the organic high molecular weight compound a thermoplastic resin having a one dimensional structure such as polymethyl methacrylate.
However, the solid composition having an ionic conductivity, which is disclosed in the prior art quoted above, has an ionic conductivity of about 10xe2x88x9210 to 10xe2x88x927Sxc2x7cmxe2x88x921, which is lower than that of the liquid nonaqueous electrolyte, and is not satisfactory in the electrochemical stability.
An object of the present invention is to provide a gel electrolyte precursor capable of providing a gel electrolyte having a high ionic conductivity and a high adhesion to the electrode.
Another object of the present invention is to provide a chemical battery exhibiting improved charge-discharge cycle characteristics and comprising a gel electrolyte having a high adhesion force to the electrolyte and an improved ionic conductivity.
Still another object of the present invention is to provide a method of manufacturing a chemical battery exhibiting improved charge-discharge cycle characteristics and comprising a gel electrolyte having a high adhesion force to the electrolyte and an improved ionic conductivity.
According to a first aspect of the present invention, there is provided a first gel electrolyte precursor, comprising a gelling agent containing at least one kind of a compound selected from the group consisting of an epoxy compound having an alicyclic structure and at least one epoxy group in a single molecule and an alicyclic epoxy resin, and an electrolyte.
According to a second aspect of the present invention, there is provided a second gel electrolyte precursor, comprising:
an electrolyte;
a halogen-containing compound;
and a compound containing at least one kind of an element selected from the group consisting of N, P and S and capable of reaction with the halogen-containing compound to form an onium salt;
wherein the halogen-containing compound contains at least one kind of the compounds represented by chemical formula (A) to chemical formula (G) given below: 
where R1 represents an organic group having a halogen atom or a halogen atom, R2 represents a divalent organic group, R3 represents a monovalent organic group, and R4 represents a monovalent organic group; 
where R1 represents an organic group having a halogen atom or a halogen atom, R1xe2x80x2 represents an organic group having a halogen atom or a halogen atom, R5 represents a divalent organic group, R6 represents a monovalent organic group, R7 represents a divalent organic group, R8 represents a monovalent organic group, and R9 represents a divalent organic group; 
where R1 represents an organic group having a halogen atom or a halogen atom, R10 represents a monovalent organic group, and R11 represents a divalent organic group; 
where R1 represents an organic group having a halogen atom or a halogen atom, R1xe2x80x2 represents an organic group having a halogen atom or a halogen atom, R12 represents a divalent organic group, and R13 represents a divalent organic group; 
where R1 represents an organic group having a halogen atom or a halogen atom, R1xe2x80x2 represents an organic group having a halogen atom or a halogen atom, R14 represents xe2x80x94(Cxe2x95x90O)xe2x80x94 or xe2x80x94CHxe2x80x94, R15 represents xe2x80x94(Cxe2x95x90O)xe2x80x94 or xe2x80x94CHxe2x80x94, R16 represents a divalent organic group, and R17 represents a divalent organic group; 
where R1 represents an organic group having a halogen atom or a halogen atom, R1xe2x80x2 represents an organic group having a halogen atom or a halogen atom, R18 represents a divalent organic group, and R19 represents a divalent organic group; 
where R1 represents an organic group having a halogen atom or a halogen atom, R1xe2x80x2 represents an organic group having a halogen atom or a halogen atom, R20 represents a divalent organic group, R21 represents a monovalent organic group, and R22 represents a divalent organic group.
According to a third aspect of the present invention, there is provided a second gel electrolyte precursor, comprising:
an electrolyte;
a halogen-containing compound;
and a compound containing at least one kind of an element selected from the group consisting of N, P and S and capable of reaction with the halogen-containing compound to form an onium salt;
wherein the compound containing at least one kind of an element selected from the group consisting of N, P and S contains at least one kind of the compounds represented by chemical formula (H) to chemical formula (N) given below: 
where R1 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R2 represents a divalent organic group, R3 represents a monovalent organic group, and R4 represents a monovalent organic group; 
where R1 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R1xe2x80x2 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R5 represents a divalent organic group, R6 represents a monovalent organic group, R7 represents a divalent organic group, R8 represents a monovalent organic group and R9 represents a divalent organic group; 
where R1 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R10 represents a monovalent organic group, and R11 represents a divalent organic group; 
where R1 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R1xe2x80x2 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R12 represents a divalent organic group, and R13 represents a divalent organic group; 
where R1 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R1xe2x80x2 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R14 represents xe2x80x94(Cxe2x95x90O)xe2x80x94 or xe2x80x94CHxe2x80x94, R15 represents xe2x80x94(Cxe2x95x90O)xe2x80x94 or xe2x80x94CHxe2x80x94, R16 represents a divalent organic group, and R17 represents a divalent organic group; 
where R1 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R1xe2x80x2 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R18 represents a divalent organic group, and R19 represents a divalent organic group; 
where R1 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R1xe2x80x2 represents an atomic group containing at least one kind of an atom selected from the group consisting of N, P and S, R20 represents a divalent organic group, R21 represents a monovalent organic group, and R22 represents a divalent organic group.
According to a fourth aspect of the present invention, there is provided a second gel electrolyte precursor, comprising:
an electrolyte;
a halogen-containing compound;
and a compound containing at least one kind of an element selected from the group consisting of N, P and S and capable of reaction with the halogen-containing compound to form an onium salt;
wherein the halogen-containing compound contains at least one kind of the compound selected from the compounds represented by chemical formula (A) to chemical formula (G), and the compound containing at least one kind of an element selected from the group consisting of N, P and S contains at least one kind of the compound selected from the compounds represented by chemical formula (H) to chemical formula (N).
According to a fifth aspect of the present invention, there is provided a first chemical battery, comprising:
a positive electrode;
a negative electrode; and
a gel electrolyte comprising a crosslinked body and an electrolyte, the crosslinked body being obtained by crosslinking at least one kind of the compound selected from the group consisting of an epoxy compound having an alicyclic structure and at least one epoxy group in a single molecule and an alicyclic epoxy resin.
According to a sixth aspect of the present invention, there is provided a first chemical battery, comprising:
a positive electrode;
a negative electrode;
a separator interposed between the positive electrode and the negative electrode; and
a gel electrolyte comprising a crosslinked body and an electrolyte, the crosslinked body being obtained by crosslinking at least one kind of the compound selected from the group consisting of an epoxy compound having an alicyclic structure and at least one epoxy group in a single molecule and an alicyclic epoxy resin, the gel electrolyte being present in at least a part of the interface between the positive electrode and the separator and in at least a part of the interface between the negative electrode and the separator.
According to a seventh aspect of the present invention, there is provided a second chemical battery, comprising:
a positive electrode;
a negative electrode; and
a gel electrolyte comprising a polymer of an onium salt formed by the reaction between a halogen-containing compound and a compound containing at least one kind of an element selected from the group consisting of N, P and S and an electrolyte;
wherein the halogen-containing compound contains at least one kind of a compound selected from the compounds represented by chemical formula (A) to chemical formula (G).
According to an eighth aspect of the present invention, there is provided a second chemical battery, comprising:
a positive electrode;
a negative electrode; and
a gel electrolyte comprising a polymer of an onium salt formed by the reaction between a halogen-containing compound and a compound containing at least one kind of an element selected from the group consisting of N, P and S and an electrolyte;
wherein the compound containing at least one kind of an element selected from the group consisting of N, P and S contains at least one kind of a compound selected from the compounds represented by chemical formula (H) to chemical formula (N).
According to a ninth aspect of the present invention, there is provided a second chemical battery, comprising:
a positive electrode;
a negative electrode; and
a gel electrolyte comprising a polymer of an onium salt formed by the reaction between a halogen-containing compound and a compound having at least one element selected from the group consisting of N, P, and S, and an electrolyte,
wherein the halogen-containing compound contains at least one kind of a compound selected from the compounds represented by chemical formula (A) to chemical formula (G), and the compound containing at least one kind of an element selected from the group consisting of N, P and S contains at least one kind of a compound selected from the compounds represented by chemical formula (H) to chemical formula (N).
According to a tenth aspect of the present invention, there is provided a third chemical battery, comprising a positive electrode, a negative electrode, and a gel electrolyte present between the positive electrode and the negative electrode, wherein the gel electrolyte comprises an electrolyte retaining polymer and an electrolyte held by the electrolyte retaining polymer, the electrolyte retaining polymer contains a crosslinked body prepared by crosslinking an epoxy resin having at least one ethylene oxide unit, at least one hydrogen atom of each of the methylene group of the ethylene oxide unit being substituted by an alkyl group.
In the third chemical battery of the present invention, it is possible for the gel electrolyte to be brought into contact with the positive electrode or the negative electrode so as to perform the function of an adhesive layer.
It is possible for the third chemical battery of the present invention to further comprise a hermetic vessel housing the electrolyte retaining polymer, the positive electrode, the negative electrode and an electrode lead. It is also possible for the electrolyte retaining polymer to be brought into contact with at least a part of the hermetic vessel or the electrode lead.
In the third chemical battery of the present invention, it is desirable for the phase of the electrolyte retaining polymer to be separated from the phase of the electrolyte.
In the third chemical battery of the present invention, it is possible for a spacer made of a porous body to be interposed between the positive electrode and the negative electrode and to form the gel electrolyte to be formed within the spacer.
In the third chemical battery of the present invention, it is possible for the positive electrode to contain a Li-containing oxide as a positive electrode active substance and for the negative electrode to contain a negative electrode active substance capable of absorbing-desorbing lithium ions.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.